There is sparse research reporting effective interventions for preventing nausea and emesis caused by concurrent chemoradiotherapy (CCRT) in locally advanced head and neck squamous cell carcinoma (LA-HNSCC).Treatment-naïve LA-HNSCC patients received intensity-modulated radiotherapy with concomitant cisplatin 100 mg/m2 (33 mg/m2/days [d]1-3) every 3 weeks for two cycles. All patients were given oral aprepitant 125 mg once on d1, then 80 mg once on d2-5; ondansetron 8 mg once on d1; and dexamethasone 12 mg once on d1, then 8 mg on d2-5. The primary endpoint was complete response (CR). Pursuant to δ = 0.2 and α = 0.05, the expected CR rate was 80%.A total of 43 patients with LA-HNSCC were enrolled. The median age was 53 years, and 86.0% were male. All patients received radiotherapy and 86.0% of patients completed both cycles as planned. The overall CR rate was 86.0% (95% confidence interval [CI]: 72.1-94.7). The CR rates for cycles 1 and 2 were 88.4% (95% CI: 74.9-96.1) and 89.2% (95% CI: 74.6-97.0). The complete protection rate in the overall phase was 72.1% (95% CI: 56.3-84.7). The emesis-free and nausea-free responses in the overall phase were 88.4% (95% CI: 74.9-96.1) and 60.5% (95% CI: 44.4-75.0), respectively. The adverse events related to antiemetics were constipation (65.1%) and hiccups (16.3%), but both were grade 1-2. There was no grade 4 or 5 treatment-related toxicity with antiemetic usage.The addition of aprepitant into ondansetron and dexamethasone provided effective protection from nausea and emesis in patients with LA-HNSCC receiving radiotherapy and concomitant high-dose cisplatin chemotherapy.© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.